Tag Archives: Evento scientifico

Technological activities to design, manufacture and test new accelerating devices using different materials and methods are under way all over the world. The main goal of these researches is to increase the accelerating gradients minimizing the probability of RF breakdown. Among the possible options, experimental results point out that relatively thick metallic coatings of Transition Metal (TM) atoms may improve the properties of standard materials like copper, in particular, the breakdown rate. In the framework of the researches performed by the INFN/DEMETRA experiment, I will present and discuss experimental data of Mo films grown on different substrates with a resistivity < 100-150 μΩ cm. Mo films are multiphase metallic systems with a not negligible contribution of disordered oxide phases: transparent and insulating phases such as MoO3 or metallic phases such as MoO2, both of high-interest also for technological applications. The interplay of nano- and micrometer-scale factors is typically at the origin of the properties and the macroscopic behavior of TM films, so that the capability to probe morphology and phase distribution of these complex systems at multiple length scale is mandatory. Different chemical and structural factors may affect the properties of Mo films and, in particular, the work function. As a consequence of the relationship between defects and work function, many transition metal (TM) oxides tend to have decreased work functions near a metal/metal-oxide interface, a behavior useful to tune the work function and the field emission, if the TM oxide and the metallic substrate is properly selected. The field …

I will discuss the recent B-physics results which indicate intriguing deviations from the Standards Model expectations. I will focus on several New Physics scenarios which are currently being explored. I will then go through several flavor physics observables and argue that they too could provide us with access to New Physics if the hadronic uncertainties are tamed by means of Lattice QCD.

The inclusive transverse-momentum spectrum of the Z boson is measured with high precision at the LHC and used a standard candle to tune Monte Carlo event generators. In turn, this implies that any change in its theoretical description will affect the Monte Carlo predictions for other Standard Model precision measurements, such as the W mass. One of the uncertainties that currently affects the theoretical prediction of the Z transverse momentum comes from the fact that in the usually used five-flavour scheme (5FS) heavy flavours are treated as massless parton in the initial state. In this work we aim at improving the description of the inclusive Z-boson transverse momentum, by including the effects of the four-flavour scheme (4FS) computation of Z production in association with bottom-quark pairs (where the bottom quarks are massive and there are no bottom PDFs in the proton), on the top of the 5FS description of the neutral-current Drell-Yan process. Finally, we estimate the impact of these effects on the measurement of the W mass.

PROTO-SPHERA is an innovative Magnetic Confinement plasma experiment for Controlled Thermonuclear Fusion research, whose aim is to form a Spherical Torus for confining a plasma of thermonuclear interest not around a metal centerpost (as in Tokamaks), but around a Plasma Centerpost. The PROTO-SPHERA experiment is producing plasma since 2 years and has reached in Argon discharges its Phase-1 target current of 8.5 kA in the Plasma Centerpost. In future (at 60 kA plasma current) magnetic plasma instabilities will kink the Plasma Centerpost to a point such as to shed a Spherical Torus around it. The experiment can at the moment produce the Plasma Centerpost only, but it is already exploring the initial phases of the kink instability. This confinement scheme, if successful, will have advantages over Tokamaks: cylindrical and not toroidal geometry of the vacuum vessel (easing access and repairs), undefined sustainment of the toroidal current within the Spherical Torus, by DC voltage applied to the Plasma Centerpost (allowed by mixed magnetic and electrostatic plasma confinement and plasma mass motion), spontaneous re-forming of the Torus in case of ‘plasma disruption’ and finally high plasma beta (unitary ratio between plasma pressure and magnetic confinement pressure, which in conventional Tokamaks is only a few %), that could minimize the size of a future Fusion reactor.

Jets, the observable remnants of energetic quarks and gluons, are fundamental objects in QCD. Jets in elementary collisions provide essential, precise tools for the study of the Standard Model and beyond, thanks to decades of development in both theory and experimental methods. In nuclear collisions at collider energies, jets are used to probe hot QCD matter though modification of their production rates and internal structure. However, jet measurements in the complex environment of nuclear collisions require new techniques, to suppress the huge uncorrelated background in such events without imposing bias on the measured distributions. Indeed, one of the most interesting and sensitive jet measurements in heavy-ion collisions is the secondary scattering of low energy jets in the Quark-Gluon Plasma, which is especially challenging due to very small signal/background. I will discuss new approaches to accurate, unbiased jet measurements over the full jet phase space in nuclear collisions, with application to data from the ALICE experiment at the LHC and the STAR experiment at RHIC. I will also discuss the potential application of these techniques to BSM measurements in proton-proton collisions, in the high luminosity era of the LHC.

We report results of baryon-hadron and meson-hadron correlations at intermediate pT, where an anomalous enhancement in the inclusive baryon-to-meson ratio has been observed in p-Pb collisions at VsNN = 5.02 TeV. The choice of the trigger pT region (2.0 pT 4.0 GeV/c) is of particular interest as it is believed to have contributions from both hard (fragmentation) and soft (hydrodynamics and/or coalescence model of hadronization) processes of particle production. The associated particles are charged hadrons with 1.0 pT 4.0 GeV/c. Using the two particle correlation technique, the multiplicity evolution of the pion- and proton-triggered jet-like yields has been studied to explore the underlying mechanisms of particle production in the intermediate pT (trigger pT) region.

Low intensity Focused Ultrasound (FUS) combined with microbubbles open the Blood-Brain Barrier (BBB) locally and noninvasively, allowing the passage of nanoparticles into the brain. However, since the quantity of particles that can be delivered with this technique depends on multiple parameters such as tissue properties, particle properties and acoustic parameters, so far a model fully predicting the result of a FUS induced BBB opening experiment is missing. During this seminar, a mathematical model depicting both the vascular permeability as a function of time and the diffusion process occurring in brain tissue will be introduced. This model takes into account acoustic pressure, particle size, blood pharmacokinetics and diffusion rates. It was validated by performing in vivo delivery of nanoparticles with different hydrodynamic diameters in rats. The match with the experimental data proves the feasibility of this novel method to successfully predict and plan drug distribution after a BBB opening experiment.

Descrizione dei Bandi ASI ed ESA di potenziale interesse INFN. Come partecipare ai Bandi ed accedere ai finanziamenti. Domande e discussione finale.

I will discuss a simple QCD axion model that arises from identifying Peccei-Quinn with Froggatt-Nielsen symmetries. The flavor problem of the Standard Model is addressed by a U(1) flavor symmetry, which naturally leads to an axion that solves the strong CP problem. The ratio of the axion mass and its coupling to photons is related to SM fermion masses and predicted within a small range, as a direct result of the observed fermion mass hierarchies. The same hierarchies determine the axion couplings to fermions, making the framework very predictive and experimentally testable by future axion and precision flavor experiments.

I will discuss my recent achievements in researches on dark dark matter and flavour anomalies.